Merge pull request #2 from mbornoz/name-validation

Allow hyphens to set hostname as barman server_name
Started refactoring
Started version with autoconfigure
First layout for autoconfiguration
to fix: postgresql configuration by postgres.pp
autoconfigure feature is completed and successfully tested (1 PostgreSQL server on 1 Barman server, 2 PostgreSQL server on 1 Barman server, 2 host groups 1 PostgreSQL-1 Barman)
Added documentation for the Barman module with 'autoconfigure' feature